Network hardware vendors including Cisco, Extreme Networks, Arastra, and others offer families of 10 Gb/sec. switch products that unify Local Area Networks (LAN) and Storage Area Networks (SAN) using protocols for Unified Network Fabric Using Fiber Channel Over Ethernet (FCOE). Cisco, for example, has introduced the Nexus family of switches (Nexus 5000 and Nexus 7000) that seamlessly communicate with disparate communications protocols such as Fiber Channel (for SANs) and Ethernet/IP (LANs).
For relatively short digital links (<20 meters), twin-ax cable is a preferred transmission medium due to the significantly lower cost per link compared to optical fiber. Twin-ax cable conductors are typically terminated on SFP+ (small form-factor pluggable) connectors, and in particular, on paddle boards or PCBs (Printed Circuit Boards) in the SFP+ pluggable connectors. At the cable termination interface, the reflections of the high-speed signals (e.g. 10 Gb/sec) are at their maximum. The SFP+ cable assemblies are used to interconnect from a Nexus 5000 (or similar) switch typically located at the top of a rack to other switches in the same or adjacent racks. Typical lengths of such connectivities are one, three, and five meters with no compensation on the connector's PCB for receive equalization and transmit pre-emphasis. Longer reaches of 10 to 20 meters are feasible and may require a pre-emphasis driver ASIC located on the connector's PCB.
However, terminating high-speed twin-ax cables to the paddle card in SFP+ cable assemblies used in Fiber Channel Over Ethernet (FCOE) deployment has been difficult. At the junction where the twin-ax conductors are soldered (or welded) to the paddle card pads, the reflection of high-speed signals (10 Gb/s) tends to be highest due to the fact that the shields are either stripped or folded back to accommodate attachment to the PCB. Improving the method of attachment (soldering, resistive welding, conductive epoxying, etc.) provides only marginal improvements in impedance matching. Further, there is a need to keep the spacing between the two pairs of twin-ax cable constant for manufacturability improvements. Protecting the soldered or welded cable-to-paddle card interface by means of strain relief is also desirable in the SFP+ cable assemblies.
In addition, the mechanism for latching the pluggable connector to the switch port and de-latching the pluggable connector from the switch port needs to be robust and reliable.
Needed is a quick and reliable method for attaching the twin-ax media to the host system.